E-books and periodicals are widely available. For current affairs, pick Pratiyogita Darpan or Manorama Yearbook.
Math problems in subjects like Algebra, Trigonometry, Differential Calculus, Vector Algebra, Matrices and Determinants, etc. will be given to you.
You should consult one book for each topic since there are two subjects with a variety of themes because the exam's extensive syllabus.
There are many books you can refer to for your preparations, but here are some of the best books for the UPSC NDA 2024 exam - General Knowledge 2023, History Of Modern India, Oxford School Atlas, Objective General English for Competitive Exams. Quantitative Aptitude for competitive examinations, etc.